Ray-tracing analysis of multicomponent whistlers propagating in the asymmetric interhemispheric plasma

Abstract

A ray-tracing model in which an interhemispheric plasma asymmetry exists, has been used to investigate the propagating characteristics of multicomponent whistlers recorded at Siple Station (L = 4.3), during local dawn on 4 Jul 1982, under very quiet geomagnetic conditions. The 3 kHz rays were started in the summer hemisphere at 300 km altitude, with vertical wave normals at 0.001 0 latitude intervals and over initial latitude ranges from which rays became trapped in eight ducts (L = 2.9 – 4.6). Final latitudes and final wave normal distributions at 300 km altitude in the winter hemisphere were calculated. The best results for trapping rays in each duct were obtained for a duct modeled ( δ = 0.15 and σ d = 50 km) to terminate at 300 km altitude and to reach full enhancement at 2100 km in both hemispheres, disregarding the seasonal variations. The oxygen ion, electron density ratio and ratio of temperature asymmetry, between summer and winter hemispheres were selected for each duct in such a way that electron density and oxygen ion concentrations were similar to data from the ISIS-2 satellite. Ray-tracing calculations were performed for 3 kHz ray that propagated in the magnetosphere in ducted mode or guided by gradient trapping.